In a single lens reflex camera, two states of observing an object through the view finder and of actually photographing the object are switched by elevating and lowering the mirror in the camera. This switching operation is the cause which generates operating sound and provides a shock to the camera. In very slow shutter speeds, the operator may feel the camera "jump" as the mirror is raised, thereby destroying the picture.
In the prior art a number of concepts have been attempted to reduce the shock or recoil in the camera as the mirror is switched. One technique is to use an air piston that damps the energy of mirror movement. This technique, while effective, is expensive and not designed for miniaturation in smaller SLR camera designs.
Also, since the mirror must be reliably switched for each shutter depression, any system for absorbing shock must work without fail over a very high repetition rate throughout the life of the camera. Moreover, in the case of motor driven shutter operation, the sequence is repeated very quickly, for example, 5 frames per second. Hence, the mechanism for damping shock must be quick acting.